This invention relates to an anti-stress agent having effects of preventing and mitigating mental and physical symptoms caused by stress, and functional food containing the anti-stress agent which is prepared by adding the anti-stress agent to yogurt, milk-containing acidified beverages, cheese, various processed foods, healthy foods, powdered foods, or granulated foods to give an anti-stress effect thereto.
In the modern society, people undergo various kinds of stress caused by highly advanced and complicated scientific technology, or drastically changing social circumstances. Particularly, in the internationalized society, complex human relationships are formed, causing mental stress. It has been reported that a variety of symptoms are caused by mental stress.
It is recognized that mental stress has a great influence on circulatory system. However, the scientific concept and definition of stress have not yet been well established, so that means of evaluation of stress still have many problems, combined with methodological difficulties. However, in the recent years, studies of stress have been made from the medical point of view.
For example, it is reported that when one undergoes stress, angiotensins II and/or vasopressin increase, and intracorporeal sodium due to sodium reabsorbancy becomes excess, which causes rise in blood pressure (Osamu Mobara et al.: Taisha, 28, 2, 323, 1991). However, suffering stress not only causes rise in blood pressure, but also influences various factors, such that it is believed to cause stomach ulcer, ischemic cardiac diseases, cerebrovascular diseases, hypertension, hyperlipemia, or the like. Therefore, though the investigation of the relationship between stress and hypertension is of importance, it is not believed that mere lowering of blood pressure will bring about the anti-stress effect.
As an agent for preventing and mitigating mental and physical symptoms caused by stress, chemically synthesized medicaments such as a tranquilizer, an antianxiety agent, and sleeping pills are presently used. However, these medicaments have habituation and side effect problems, so that it is not preferable to use them daily for the purpose of preventing mental and physical symptoms caused by stress. Accordingly, foods having the anti-stress effect are desired and are under development, which can be taken repeatedly and daily without any problems with safety, and which can mitigate and prevent mental and physical symptoms caused by stress. For example, an anti-stress agent containing as an effective ingredient L-theanine contained in tea leaves, is proposed in Japanese Laid-open Patent Application No. 6-100442, which can be mixed in tasty beverages (nutrient supplementary drinks) for daily uptake. Further, a stress relieving effect of fragrance is also reported (FRAGRANCE JOURNAL:1991-11, 44). However, there has not been reported that lactic acid bacteria-fermented milk has the effect of mitigating and preventing mental and physical symptoms caused by stress.
It is therefore an object of the present invention to provide an anti-stress agent which can fulfill the social demand as mentioned above, which can be taken repeatedly and daily without any problems with safety, and which can mitigate and prevent mental and physical symptoms caused by stress; and its use.
It is another object of the present invention to provide functional food having an anti-stress effect which can fulfill the social demand as mentioned above, and which can be taken as food repeatedly and daily without any problems with safety; and its use.
The present inventors have made intensive studies to find a substance which can fulfill the social demand as mentioned above, which can be used in food, and which can be taken repeatedly without any problems with safety. As a result, they have noticed that fermented sour milk has a superior anti-stress effect, and completed the present invention.
According to the present invention, there is provided an anti-stress agent containing as effective agent at least one fermented sour milk.
According to the present invention, there is also provided a functional food having anti-stress effect containing the anti-stress agent.
According to the present invention, there is further provided use of the anti-stress agent or the functional food for the manufacture of a drug for the treatment of stress.
According to the present invention, there is also provided a method of treatment of human or animal stress comprising oral administration of the anti-stress agent or the functional food.